Hi Tercol. I find they are hardy, but will only be semi-evergreen at best. I'd go by the foliage...if ts been imported from a poly tunnel it will be very fresh young foliage which you'll lose if you plant it out now and we get cold weather. I think you've done the right thing keeping it under cover. i'd wait until the weather is a bit milder...who knows when that will be...and plant it out then. I bought one recently and planted it straight outside, but it was a sale plant that had been outdoors all winter so it won't come to any more harm in the ground than it would have staying in its pot. If you think yours is similarly hardened off, then just get it in the ground.